Female Embryos More Fragile Than Male

Scientists have claimed that female embryos are more likely to die during pregnancy.

11:23 31 March 2015

Scientists have overturned a long-held belief that male embryos are more vulnerable in the first months life saying that female are more likely to die during pregnancy. If the findings are indeed true and supported with more evidence, it could shed a new light on the different challenges faced by males and females during the early phases of development. 

 

Steven Orzack, a biologist who led the research at the Fresh Pond Research Institute in Cambridge, Massachusetts, said: “This is an excellent example of an idea in science that’s had wide circulation, but where the empirical basis was ambiguous. It gets in textbooks and then it’s viral. No one really sat down and said ‘let’s try and make sense of all this’.”

 

The scientists have studied around 140,000 embryos that are conceived using assistive reproductive technologies to assess the mortality from the first few days after conception. The data shows that male embryos were more likely to be abnormal and that many of these embryos die a week or two after conception. It also found that female embryos are at greatest risk due to the way X chromosomes are inactivated in cells.